An Australian couple has denied abandoning a boy born with Down syndrome to a surrogate they engaged in Thailand.

The plight of six-month-old Gammy, who also has a hole in his heart, has prompted calls for reform of surrogacy services in Australia.

Impoverished mother Pattaramon Chanbua told the ABC she gave birth to twins after agreeing to be a surrogate for the West Australian couple with a promised payment of about $16,000.

She claims the couple, who have not been identified, rejected Gammy and returned to Australia with his healthy sister.

But the baby girl's Australian father says the clinic's doctor only told them about the girl.

He has told the ABC they had a lot of trouble with the surrogacy agency and had been told it no longer existed.

Ms Chanbua said her doctors, the surrogacy agency and the baby's parents knew he was disabled at four months, but did not inform her until the seventh month when the agency asked her - at the parents' request - to abort the disabled foetus.

She told the ABC she refused the couple's request to terminate the pregnancy because in Thai culture it was considered sinful, but she could not afford Gammy's medical treatment.

"We've rallied round to support this child via the GoFundMe campaign, so I think we're happy that he stays in Thailand with his surrogate mum right now. But we don't want to see this kind of thing happening again."

Mr Everingham said the laws and government support for couples investigating and pursuing surrogacy were not adequate.

"We do want to see the Australian Government putting money into surrogacy education and support for families who are at the moment going overseas with the Government really just turning their back on them," he said.

Prime Minister Tony Abbott said it was "an incredibly sad story" and the Government would look into the case.

In Australia, people from New South Wales, Queensland and the ACT are prohibited from entering a commercial surrogacy agreement overseas.

In Thailand the ruling military is cracking down on the often unregulated IVF and surrogacy industry.

The Department of Foreign Affairs says it is concerned by the reports and is consulting with Thai authorities.

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